I. Field of the Invention
The present invention relates generally to alarm systems and, more particularly, to an alarm system which detects seismic tremors.
II. Description of the Prior Art
At present, no accurate means exists for pinpointing in advance either the time and place of earthquake activity. Earthquake shocks are sequential in nature with the typically more destructive S and L waves following the fast moving but less severe P waves by several seconds when in very close proximity to the epicenter of the earthquake. At more distant locations from the epicenter of the earthquake, the P waves may precede and S and L waves by several minutes.
The greatest danger to human life during earthquake activity is the collapse of building structures while persons are entrapped within them. However, since the less severe P waves of the earthquake precede the more severe S and L waves, there is often sufficient time available for persons to enhance their personal safety, for example by leaving the building structure, avoiding windows, and the like. Unfortunately, many people either do not perceive that an earthquake is in progress, or require some objective confirmation before taking appropriate action; thus, their response may be delayed until the more severe earthquake shocks, i. e. the S and L waves, have already begun.
There have, of course, been a number of previously known seismic graphs for detecting and oftentimes recording intensities of seismic tremors. One type of previously known device, however, is generally complex and expensive in construction and, therefore, economically unsuitable for home or personal use. On the other hand, other types of previous known devices do not distinguish or provide separate alarms indicative of the intensity of the tremor.